The analysis of machine tools shows that, despite sufficient cooling capacity, thermo-elastic deformation is insufficiently compensated because component dependent heat losses and heat dissipation are poorly coordinated in time and location. This leads to impairments of machine performance and production quality. The paper summarizes experimental and simulative investigations on cooling in machine tools. At component level, convection in the channel is modelled to derive measures for effective cooling. Moreover, thermo-energetic properties of a machining center are measured. This is used to develop a thermo-hydraulic network model for cooling and to investigate various measures for structure and control optimization. Finally, these results are validated on test-rigs.